Signs vary widely based on the specific EDS the person has. In each case, however, the signs are ultimately due to faulty or reduced amounts of collagen. An EDS typically affects the joints, skin, and blood vessels. Following is a list of major signs and symptoms.[citation needed]

Cranial vertebral instability: caused by trauma(s) to the head and neck areas such as concussion and whiplash. Ligaments in neck are unable to heal properly, therefore, the neck structure does not have the ability to support the skull, which can then sink into the brain stem blocking the normal flow of cerebral spinal fluid, leading to issues related to the autonomic nervous system failing to work properly.[31]

Celiac disease: it may be associated with EDS. Also, can be misdiagnosed as EDS due to common symptoms that may appear in both diseases, including fatigue, pain, gastrointestinal complaints, or cardiovascular autonomic dysfunction.[32]

The collagen fibril and EDS. (a) Normal collagen fibrils are of uniform size and spacing. Fibrils from a patient with dermatosparaxis (b) show dramatic alterations in fibril morphology with severe effects on tensile strength of connective tissues. Patients with classical EDS (c) show composite fibrils. Fibrils from a TNX-deficient patient (d) are uniform in size and no composite fibrils are seen. TNX-null (e) fibrils are less densely packed and not as well aligned to neighboring fibrils.

Only some Ehlers–Danlos syndromes can be positively identified as tied to specific genetic variation.

Mutations in these genes usually alter the structure, production, or processing of collagen or proteins that interact with collagen. Collagen provides structure and strength to connective tissue. A defect in collagen can weaken connective tissue in the skin, bones, blood vessels, and organs, resulting in the features of the disorder.[citation needed]

Inheritance patterns depend on the specific Ehlers–Danlos syndrome. Most forms of Ehlers–Danlos syndromes are inherited in an autosomal dominant pattern, which means only one of the two copies of the gene in question must be altered to cause a disorder. The minority are inherited in an autosomal recessive pattern, which means both copies of the gene must be altered for a person to be affected by a disorder. It can also be an individual (de novo or "sporadic") mutation. Refer to the summary for each Ehlers–Danlos syndrome for a discussion of its inheritance pattern.[35]

A diagnosis can be made by an evaluation of medical history and clinical observation. The Beighton criteria are widely used to assess the degree of joint hypermobility. DNA and biochemical studies can help identify affected individuals. Diagnostic tests include collagen gene mutation testing, collagen typing via skin biopsy, echocardiogram, and lysyl hydroxylase or oxidase activity. However, these tests are not able to confirm all cases, especially in instances of an unmapped mutation, so clinical evaluation by a geneticist remains essential. If there are multiple affected individuals in a family, it may be possible to perform prenatal diagnosis using a DNA information technique known as a linkage study.[citation needed] There is poor knowledge about EDSs among practitioners.[36][37]

As of 2017, 13 Ehlers–Danlos syndromes had been characterized, with a significant overlap in features.[38]

Hypermobile EDS (hEDS) characterized primarily by joint hypermobility affecting both large and small joints, which may lead to recurrent joint dislocations and subluxations (partial dislocation). In general, people with this type have soft, smooth and velvety skin with easy bruising and chronic pain of the muscles and/or bones.[38]

Classical EDS - associated with extremely elastic (stretchy), smooth skin that is fragile and bruises easily; wide, atrophic scars (flat or depressed scars); and joint hypermobility. Molluscoid pseudotumors (calcified hematomas over pressure points such as the elbow) and spheroids (fat-containing cysts on forearms and shins) are also frequently seen. Hypotonia and delayed motor development may occur.[38]

Vascular EDS - characterized by thin, translucent skin that is extremely fragile and bruises easily. Arteries and certain organs such as the intestines and uterus are also fragile and prone to rupture. People with this type typically have short stature; thin scalp hair; and characteristic facial features including large eyes, a thin nose, and lobeless ears. Joint hypermobility is present, but generally confined to the small joints (fingers, toes). Other common features include club foot; tendon and/or muscle rupture; acrogeria (premature aging of the skin of the hands and feet); early onset varicose veins; pneumothorax (collapse of a lung); recession of the gums; and a decreased amount of fat under the skin.[38]

Kyphoscoliosis EDS - associated with severe hypotonia at birth, delayed motor development, progressive scoliosis (present from birth), and scleral fragility. Affected people may also have easy bruising; fragile arteries that are prone to rupture; unusually small corneas; and osteopenia (low bone density). Other common features include a "marfanoid habitus" which is characterized by long, slender fingers (arachnodactyly); unusually long limbs; and a sunken chest (pectus excavatum) or protruding chest (pectus carinatum).[38]

Arthrochalasia EDS - characterized by severe joint hypermobility and congenital hip dislocation. Other common features include fragile, elastic skin with easy bruising; hypotonia; kyphoscoliosis (kyphosis and scoliosis); and mild osteopenia.[38]

Periodontal EDS (pEDS) characterized by severe and intractable periodontitis of early onset (childhood or adolescence), lack of attached gingiva, pretibial plaques; and family history of a first-degree relative who meets clinical criteria.[38]

Several disorders share some characteristics with EDSs. For example, in cutis laxa the skin is loose, hanging, and wrinkled. In an EDS, the skin can be pulled away from the body but is elastic and returns to normal when let go. In Marfan syndrome, the joints are very mobile and similar cardiovascular complications occur. People with an EDS tend to have a "Marfanoid" appearance (e.g., tall, skinny, long arms and legs, "spidery" fingers). However, physical appearance and features in several EDSs also have characteristics including short stature, large eyes, and the appearance of a small mouth and chin, due to a small palate. The palate can have a high arch, causing dental crowding. Blood vessels can sometimes be easily seen through translucent skin, especially on the chest. The genetic connective tissue disorder, Loeys-Dietz Syndrome, also has symptoms that overlap with EDSs.[39]

In the past, Menkes disease, a copper metabolism disorder, was thought to be an EDS. It is not uncommon for patients to be misdiagnosed with fibromyalgia, bleeding disorders or other disorders that can mimic EDS symptoms. Because of these similar disorders and complications that can arise from an unmonitored case of an EDS, a correct diagnosis is important.[40]Pseudoxanthoma elasticum (PXE) is worth consideration in diagnosis.[citation needed]

No cure is known for Ehlers–Danlos syndromes. Treatment is supportive. Close monitoring of the cardiovascular system, physiotherapy, occupational therapy, and orthopedic instruments (e.g., wheelchairs, bracing, casting) may be helpful. This can help with stabilizing the joints and preventing injury. Orthopedic instruments are helpful for the prevention of further joint damage, especially for long distances, although it is advised that individuals not become dependent on them until other mobility options have been exhausted. Patients should avoid activities that cause the joint to lock or overextend.[citation needed]

A physician may prescribe casting to stabilize joints. Physicians may refer a patient to an orthotist for orthotic treatment (bracing). Physicians may also consult a physical and/or occupational therapist to help strengthen muscles and to teach people how to properly use and preserve their joints.[41][42]

Aquatic therapy promotes muscular development and coordination.[43] With manual therapy, the joint is gently mobilized within the range of motion and/or manipulations.[41][42] If conservative therapy is not helpful, surgical joint repair may be necessary. Medication to decrease pain or manage cardiac, digestive, or other related conditions may be prescribed. To decrease bruising and improve wound healing, some patients have responded to vitamin C.[44] Special precautions are often taken by medical care workers because of the sheer amount of complications that tend to arise in EDS patients. In vascular EDS, signs of chest or abdominal pain are considered trauma situations.[citation needed]

In general, medical intervention is limited to symptomatic therapy. Before pregnancy, patients with an EDS should have genetic counseling and familiarize themselves with the risks to their own bodies that pregnancy poses. Children with an EDS should be provided with information about their disorder so they can understand why they should avoid contact sports and other physically stressful activities. Children should be taught that demonstrating the unusual positions they can maintain due to loose joints should not be done as this may cause early degeneration of the joints. Emotional support and behavioral[clarification needed] and psychological therapy can be useful. Support groups can be immensely helpful for patients dealing with major lifestyle changes and poor health. Family members, teachers, and friends should be informed about EDS so they can accept and assist the child.[citation needed]

The instability of joints, leading to (sub)luxations and joint pain, often require surgical intervention in people with an Ehlers–Danlos syndrome. Instability of almost all joints can happen but appear most often in the lower and upper extremities, with the wrist, fingers, shoulder, knee, hip, and ankle being most common.[41]

Common surgical procedures are joint debridement, tendon replacements, capsulorraphy, and arthroplasty. Studies have shown that after surgery, degree of stabilization, pain reduction, and patient satisfaction can improve, but surgery does not guarantee an optimal result: Patients and surgeons report being dissatisfied with the results. Consensus is that conservative treatment is more effective than surgery,[21] particularly since patients have extra risks of surgical complications due to the disease. Three basic surgical problems arise due to an EDS: the strength of the tissues is decreased, which makes the tissue less suitable for surgery; the fragility of the blood vessels can cause problems during surgery; and wound healing is often delayed or incomplete.[41] If considering surgical intervention, it would be prudent to seek care from a surgeon with extensive knowledge and experience in treating people with an EDS and joint hypermobility issues.[citation needed]

Studies have shown that local anesthetics, arterial catheters and central venous catheters cause a higher risk in haematoma formation in people with an Ehlers–Danlos syndrome. People with an Ehlers–Danlos syndrome also show a resistance to local anaesthetics.[45] Resistance to xylocaine and bupivacaine is not uncommon, and carbocaine tends to work better in people with an EDS. Special recommendations for anesthesia in people with an EDS are prepared by orphananesthesia and deal with all aspects of anesthesia for people with an EDS.[46] Detailed recommendations for anesthesia and perioperative care of people with an EDS should be used to improve safety.[47]

Surgery in people with an Ehlers–Danlos syndrome requires careful tissue handling and a longer immobilization afterward.[citation needed]

The outlook for individuals with an EDS depends on the specific EDS they have. Symptoms vary in severity, even in the same disorder, and the frequency of complications varies. Some people have negligible symptoms while others are severely restricted in daily life. Extreme joint instability, chronic musculoskeletal pain, degenerative joint disease, frequent injuries and spinal deformities may limit mobility. Severe spinal deformities may affect breathing. In the case of extreme joint instability, dislocations may result from simple tasks such as rolling over in bed or turning a doorknob. Secondary conditions such as autonomic dysfunction or cardiovascular problems, occurring in any type, can affect prognosis and quality of life. Severe mobility-related disability is seen more often in hypermobile EDS than in classical EDS or vascular EDS.[citation needed]

Although all EDSs are potentially life-threatening, the majority of patients have a normal lifespan. However, those with blood vessel fragility have a high risk of fatal complications, including spontaneous arterial rupture, which is the most common cause of sudden death. The median life-expectancy in the population with vascular EDS is 48 years.[48]

Ehlers–Danlos syndromes are inherited disorders estimated to occur in about 1 in 5,000 births worldwide. Initially, prevalence estimates ranged from 1 in 250,000 to 1 in 500,000 people, but these estimates were soon found to be too low as the disorders received further study and medical professionals became more adept at diagnosis. Ehlers–Danlos syndromes may be far more common than the currently accepted estimate due to the wide range of severities with which the disorder presents.[49]

The prevalence of the 13 disorders differs dramatically. The most commonly occurring is hypermobile EDS, followed by classical EDS. The other Ehlers–Danlos syndromes are very rare. For example, fewer than ten infants and children with dermatosparaxis EDS have been described worldwide. Some Ehlers–Danlos syndromes are more common in Ashkenazi Jews. For example, the chance of being a carrier for dermatosparaxis EDS is 1 in 248 in Ashkenazi Jews, whereas the prevalence of this mutation in the general population is 1 in 2,000.[50]

In the 19th century, there were several sideshow performers billed as The Elastic Skin Man, The India Rubber Man and Frog Boy. They included such well-known individuals (in their time) as Felix Wehrle, James Morris and Avery Childs.[51]

Adult film star Mandy Morbid has discussed the impact her EDS has on her mobility and her life.[55]

Rei Haycraft, lead singer for the hard rock band Raimee, artist, and illustrator, has created songs and a documentary about living with an Ehlers–Danlos syndrome, as well as written songs about its impact on her life.[56][57]

American disability rights activist Annie Segarra has an EDS, and talks about the condition on her Annie Elainey YouTube channel.[58]

Ehlers–Danlos-like syndromes have been shown to be hereditary in Himalayan cats, some domestic shorthair cats, and in certain breeds of cattle. It is seen as a sporadic condition in domestic dogs.[citation needed]

Degenerative suspensory ligament desmitis (DSLD) is a similar condition seen in many breeds of horses. It was originally notated in the Peruvian Paso and thought to be a condition of overwork and older age. However, the disease is being recognized in all age groups and all activity levels. It has even been noted in newborn foals.[citation needed] The latest research has led to the renaming of the disease as equine systemic proteoglycan accumulation, after the possible systemic and hereditary components being delineated by the University of Georgia.[64][65]